Vehicular exterior rearview mirror assembly with blind zone indicator

ABSTRACT

A vehicular exterior rearview mirror assembly includes a mounting structure, a mirror reflective element, a mirror back plate, a heater element, and a blind zone indication module. The heater element is disposed between the mirror back plate and the mirror reflective element. The blind zone indication module includes a diffuser and a housing that houses a circuit element and a light source. The circuit element includes electrically conductive terminals that are in electrical connection with circuitry of the circuit element and that are disposed at a connector portion of the housing that is configured to connect to a wire harness to electrically power circuitry of the circuit element when the vehicular exterior rearview mirror assembly is mounted and used at a vehicle. The blind zone indication module is associated with a blind spot detection system of a vehicle at which the vehicular exterior rearview mirror assembly is mounted and used.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a division of U.S. patent application Ser.No. 17/448,952, filed Sep. 27, 2021, now U.S. Pat. No. 11,631,332, whichis a continuation of U.S. patent application Ser. No. 16/840,580, filedApr. 6, 2020, now U.S. Pat. No. 11,132,903, which is a division of U.S.patent application Ser. No. 15/700,271, filed Sep. 11, 2017, now U.S.Pat. No. 10,614,719, which is a continuation of U.S. patent applicationSer. No. 14/849,998, filed Sep. 10, 2015, now U.S. Pat. No. 9,761,144,which claims the filing benefits of U.S. provisional applications, Ser.No. 62/113,555, filed Feb. 9, 2015, and Ser. No. 62/049,077, filed Sep.11, 2014, which are hereby incorporated herein by reference in theirentireties.

FIELD OF THE INVENTION

The present invention relates to exterior rearview mirror assembliesand, more particularly, to an exterior rearview mirror assembly having ablind spot/object detection indicator and/or a lane change aid (LCA)indicator and/or a turn signal or other indicator at the exteriorrearview mirror assembly.

BACKGROUND OF THE INVENTION

It is known to provide a blind spot detection/LCA system for a vehiclethat detects the presence of another vehicle or object in the lane nextto the host vehicle, where it may be difficult for the driver of thehost vehicle to determine whether or not there is another vehicle orobject adjacent to the host vehicle. Such a blind spot detection/LCAsystem often includes a visual indicator that visually indicates thedetection of another vehicle or object to the driver of the hostvehicle. It is also know to provide a turn signal indicator that isactivated when a turn signal is activated by the driver of the equippedvehicle so as to provide an indication of the vehicle turning orchanging lanes to the driver of a vehicle in an adjacent lane to thehost or subject vehicle or to another person external to the host orsubject vehicle. The visual indicator or indicators (commonly a lightemitting diode or the like) of such systems is/are often located at themirror reflective element of the exterior rearview mirror assembly.

A variety of interior and exterior mirror assemblies with indicators areknown in the art, such as described in U.S. Pat. Nos. 5,355,284;5,788,357; 6,257,746; 6,005,724; 5,481,409; 6,111,683; 6,045,243;6,264,353; 6,512,624; 6,356,376; 2,263,382; 2,580,014; 3,266,016;4,499,451; 4,588,267; 4,630,904; 4,623,222; 4,721,364; 4,906,085;5,313,335; 5,587,699; 5,575,552; 5,436,741; 5,587,699; 5,938,320;6,700,692 and 5,786,772, and International Publication WO 95/30495,which are all hereby incorporated herein by reference in theirentireties.

SUMMARY OF THE INVENTION

The present invention provides a blind zone or blind spot indicator orlane change assist (LCA) indicator or turn signal indicator or otherindicator that is disposed at and may be integral with the mirrorreflector carrier or back plate of the mirror reflector sub-assembly soas to be positioned at and attached to the mirror reflective elementwhen the back plate is adhered or otherwise attached at the back of themirror reflective element. Preferably, the signal indicator is providedas a sealed or substantially sealed unit or module that can be snappedinto or otherwise attached or secured (preferably mechanically butoptionally adhesively) at the mirror back plate (and does sosubstantially or wholly sealingly to limit or substantially precludewater ingress to the module so that the module and back plate aresubstantially water impervious), preferably at the mirror sub-assemblymanufacturing operation when the mirror reflective element (and anyassociated heater pad or other item or element) is joined to the mirrorback plate.

The blind zone indicator of the present invention includes a housingwith a diffuser that is angled so that light emitted by one or morelight sources (such as light emitting diodes) at the back or rearportion of the diffuser and housing is directed generally towards theside of the vehicle for viewing by the driver of the vehicle. Thediffuser includes a baffle or light blocking or occluding elementdisposed in front of or at least partially in front of each of the lightemitting diodes to limit or partially occlude direct illumination of adiffuser cover by the light sources and thus to limit bright spots whenthe indicator is activated and viewed. The present invention thusprovides a mirror reflector carrier or back plate with an integratedblind spot or blind zone indicator (or a turn signal indicator and/orother indicator/indicators) that provides enhanced viewing of theilluminated icon of the indicator by the driver of the vehicle (or byothers such as drivers of other vehicles approaching or overtaking orbeing overtaken by the equipped vehicle).

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of an exterior mirror assembly with a blind zoneindicator or indicator module in accordance with the present invention,shown as viewed in the direction of travel of the vehicle;

FIG. 2 is a plan view of a back plate for attaching at a mirrorreflective element, with an indicator module disposed at the back platein accordance with the present invention;

FIG. 3 is a plan view of the front side of the back plate and indicatormodule of FIG. 2 ;

FIG. 4 is a side view of the back plate and indicator module of FIG. 2 ;

FIG. 5 is an enlarged perspective view of a portion of the back plateand indicator module of FIG. 2 ;

FIG. 6 is a sectional view of the back plate and indicator module of thepresent invention;

FIG. 7 is a perspective view of the indicator module of the presentinvention;

FIG. 8 is another perspective view of the indicator module of thepresent invention;

FIG. 9 is a perspective view of the indicator module of the presentinvention, shown without the module housing to show additional details;

FIGS. 10 and 11 are exploded perspective views of the indicator moduleof the present invention;

FIG. 12 is a sectional view of the indicator module of the presentinvention;

FIG. 13 is a perspective view of the indicator module of the presentinvention, shown with the icon mask removed;

FIG. 14 is another sectional view of the indicator module of the presentinvention;

FIG. 15 is an electrical schematic of a circuit for controlling thelight emitting diodes of the indicator module of the present invention,without overvoltage protection;

FIG. 16 is an electrical schematic of another circuit for controllingthe light emitting diodes of the indicator module of the presentinvention, with overvoltage protection;

FIG. 17 is an exploded perspective view of another indicator module ofthe present invention, with louvers disposed between apertures of thelight sources of the module;

FIG. 18 is a perspective view of the diffuser of the indicator module ofFIG. 17 ;

FIGS. 19 and 20 are exploded perspective views of the indicator moduleof the present invention;

FIGS. 21 and 22 are perspective views of module covers with louvers inaccordance with the present invention;

FIGS. 23 and 24 are perspective views of indicator modules with louversin accordance with the present invention;

FIGS. 25 and 26 are plan views of masks of the indicator module, showingan LCA icon (FIG. 25 ) and a BZI icon (FIG. 26 );

FIG. 27 is a plan view of another indicator module of the presentinvention;

FIG. 28 is a perspective view of another indicator module of the presentinvention; and

FIG. 29 is an exploded perspective view of the indicator module of FIG.28 .

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and the illustrative embodiments depictedtherein, an exterior rearview mirror assembly 10 for a vehicle includesa mirror reflector sub-assembly 12 and a mirror shell or casing 14 (FIG.1 ). Mirror assembly 10 is mounted at the side 16 a of a host or subjectvehicle 16. The mirror reflector sub-assembly 12 includes a mirrorreflective element 18 and a mirror reflector carrier or back plate 20(FIGS. 2-5 ) attached to or mounted to or adhered to a rear surface ofthe mirror reflective element 18. Mirror assembly 10 includes anindicator or display element or device or signal indication module 22that is disposed at back plate 20 and behind reflective element 18, andthat is operable to provide a display or indication 23 at the reflectiveelement for viewing the display or indication through the mirrorreflective element.

Signal indication module 22 includes a housing 24 (that is received intoor attached to an indicator receiving portion or mounting portion orstructure of back plate 20 so as to be disposed generally at a rearsurface of a planar portion of back plate 20) and an illumination sourceor indicator, such as one or more light emitting diodes (LEDs) or othersuitable illumination source. In the illustrated embodiment, the lightsource comprises a pair of light emitting diodes 28, 30, with each lightemitting diode being independently energized or powered for illuminatinga respective icon established at a mask 36 disposed at a front diffuser38 of the indicator module. Signal indication module 22 includes adiffuser element 26 that is formed to angle the light emitting diodes28, 30 such that light emitted by the light emitting diodes, whenactivated or energized or powered, is principally viewed by the driverof the vehicle. The diffuser element 26 includes a baffle 34 disposeddirectly in front of or partially in front of the respective lightemitting diode, and partially but not fully occluding light emitted bythe light source or light emitting diode, to limit or reduce brightspots of the light emitted by the light emitting diode at the frontdiffuser to reduce bright spots or hot spots that may otherwise beviewed by the driver of the vehicle, as discussed below.

In the illustrated embodiment, the signal indication module 22 comprisesa blind zone indicator for an object detection in a blind spot detectionsystem or LCA system (with the indicator module being angled andoperated to provide a signal that is principally viewable by the driverof the vehicle). Optionally, the indicator module may also or otherwiseinclude a display device or indicator for a turn signal indicator orsignal indication module or other indicator device. The blind zone orsignal indicator assembly or indicator module of the present inventionmay utilize aspects of the indicators described in U.S. Pat. Nos.8,786,704; 8,058,977; 7,944,371; 7,581,859; 7,038,577; 6,882,287;6,198,409; 5,929,786 and/or 5,786,772, and/or International PublicationNos. WO 2007/005942 and/or WO 2006/124682, which are all herebyincorporated herein by reference in their entireties.

As shown in FIGS. 3 and 4 , signal indication module 22 includes acircuit element 32, such as a printed circuit board or the like (such asa rigid or flexible circuit board or element), with a pair ofillumination sources or LEDs 28, 30 disposed thereat (such as surfacemounted or otherwise disposed LEDs or other suitable or equivalent lightsource), although more illumination sources or LEDs may be providedwhile remaining within the spirit and scope of the present invention.Circuit element 32 is attachable at or positioned at a rear portion 26 aof the diffuser element 26 and disposed in housing 24 (such as receivedat a pocket or receiving portion formed at the rear portion of thediffuser element 26), whereby the illumination sources 28, 30 arelocated at the rear portion of the housing and at an opposite end of thehousing from the reflective element 18.

In the illustrated embodiment, the diffuser element 26 (with circuitelement or PCB attached thereat) is received in and attached at (such asvia a snap attachment) housing 24 to substantially encase the circuitelement 32 within the module. Optionally, diffuser element 26 may snapand/or or may be sealed or adhered or welded to the housing 24 tosubstantially seal circuit element 32 within the housing of the signalindication module. As can be seen in FIGS. 9-11 , circuit element 32includes electrical terminals or connectors 32 a that are in electricalor conductive communication with illumination sources 28, 30 and thatelectrically connect the circuitry and light sources to electrical poweror electrical control at the mirror assembly when the signal indicationmodule is attached to the back plate and installed at the mirror casing.Optionally, connectors 32 a connect to a mating connector 33, which isdisposed at an opening in housing 24 for electrical connection to aconnector of the mirror assembly or vehicle to provide power and/orcontrol to the signal indication module when the module is mounted to orattached to the back plate and installed at the mirror casing.

Signal indication module 22 includes an icon element or indicia elementor masking element 36 that is disposed at a forward end region orportion 26 b of diffuser element 26 so as to be disposed at the rear ofthe reflective element when the signal indication module 22 is attachedto the back plate 20. The indicia element is formed to provide thedesired or appropriate icon or icons for viewing by the driver of thevehicle (for a blind spot detection system application) when the icon oricons of the indicia element is/are backlit or illuminated by therespective illumination source 28, 30. Optionally, the walls or surfacesof diffuser element may comprise highly specularly and/or diffuselylight reflecting inner surfaces so as to enhance diffuse reflection ofincident light to enhance the intensity of illumination that exits theindicator module through the indicia element. For example, the diffuserwall may be molded of a white plastic material or resin, such as an ABSor an ABS/polycarbonate polymeric resin material or the like.

Optionally, and desirably, a diffuser cover or film or element 38 may bedisposed at the front (or rear) of the indicia element 36 to diffuse thelight emitted by the illumination sources 28, 30 to provide more uniformillumination of the indicia element 36 (when the illumination sourcesare activated) as viewed by the driver of the vehicle. The diffuserelement 38 and indicia element 36 may be attached or adhered at thefront end portion or surface of the diffuser element 26 (and thediffuser element may also or otherwise be adhered to the rear of thereflective element when the indicator module is attached at the backplate). Optionally, the mirror reflective element may comprise atransflective mirror reflective element having a mirror reflector thatis partially transmissive of light so that the illuminated icons areviewable through the reflective element by the driver of the vehicle.Optionally, and as shown in FIG. 12 , the mirror reflective element 18′may comprise a mirror glass substrate having a reflector coating at itsouter or front surface, with icons 18 a′ formed (via masking orablation) through the reflector coating so that the illuminated icons ofthe signal module are viewable through the ablated windows of thereflective element by the driver of the vehicle.

To limit or reduce or avoid hot spots (areas of excessive brightness),on the parts of the front diffuser that are closer to the light sources(LEDs), the baffles 34 are incorporated in the diffuser element 26 andat or in front of the light sources 28, 30 so as to cast a diffuseshadow from the light radiating directly from the respective lightsource 28, 30. This serves to balance the amount of light projected ontothe various areas of the mask 36 and front diffuser 38. Areas of thefront diffuser that are further away from the light source(s) receivemore direct radiation from the light source(s), while areas of the frontdiffuser that are closer to the light source(s) receive less directradiation from the light source(s), such that the indicator moduleprovides more uniform lighting of the icon or icons and thus providesenhanced viewing of the indicator icons by the driver of the vehicle.

In the illustrated embodiment, and such as can be understood withreference to FIGS. 12 and 13 , the baffles are formed as part of therear diffuser 26 (such as during the molding of the plastic diffuserbody) and protrude from the angled wall of the diffuser so as to bedisposed at least partially in front of the respective LED to block orlimit direct light emitted by the LED, so that the light emitted by thelight source or light emitting diode is partially but not fully occludedby the baffle 34. In the illustrated embodiment (and such as can be seenwith reference to FIG. 12 ), the LEDs are disposed at an end region orapex region 34 a of the conical-shaped walls of the diffuser element andthe baffles are formed at and protrude from a side or wall portion (ofthe conical formed wall or walls) of the diffuser element that isoutboard of the respective LED, and the baffles protrude or extendinward towards an axis 34 b of the conical-shaped walls, such that thebaffle is disposed at least partially in front of the respective LED andblocks or substantially limits light emitted by the LED in the outboarddirection to reduce viewability of the emitted light by drivers of othervehicles in the side lane adjacent to the equipped vehicle. The bafflesare oriented to be in a plane that is generally normal to the LED andcircuit element so as to be disposed in the path of light emitted by theLED.

The baffles thus extend from the outboard portions of the diffuser(outboard of the respective LED) to limit or block light emitted by therespective LED from being emitted outboard towards drivers of othervehicles. The baffles do not protrude fully over or in front of therespective LED so that light emitted by the respective LED is readilyviewable by the driver of the equipped vehicle. Although shown anddescribed as being formed or molded with the diffuser element (and withthe angled surfaces or conical surfaces or walls of the element), it isenvisioned that the baffles may be separately formed and attached orclipped at the diffuser element so as to be positioned and oriented infront of or partially in front of the respective LED in the selectedmanner.

The baffles may comprise generally disc-shaped or circular-shapedelements or baffles and may be sized to provide the desired degree ofblocking of light emitted by the respective LEDs. The size of thebaffles or degree in which the baffles protrude in front of therespective LEDs may vary depending on the particular application of themodule. Optionally, for a turn signal indicator module application, thebaffles may be formed at and protrude from a side or wall portion (ofthe conical formed wall or walls) of the diffuser that is inboard of therespective LED, such that the baffle blocks or substantially limitslight emitted by the respective LED in the inboard direction to reduceviewability of the emitted light by the driver of the equipped vehicle.

Illumination sources 28, 30 are independently or individually operableor activatable or energizable to provide illumination at and through oralong the diffuser element 26, whereby the illumination is transmittedthrough the mask or indicia element 36 and front diffuser 38 and throughthe aperture in back plate 20 and through the reflective element so asto be viewable through the mirror reflective element by a person viewingthe mirror assembly 10. The signal indication module 22 may comprise ablind spot or object detection indicating device or module that isoperable to indicate to the driver of the subject or host vehicle thatan object or other vehicle is detected at the side or blind spot regionof the host vehicle by a blind spot detection system. Optionally,aspects of the blind zone indicator module of the present invention maybe used for a turn signal indicating device or module that is operableto indicate to the driver or passenger of another vehicle that theequipped vehicle is turning or changing lanes, or other forms or typesof display or illumination or indicating devices or modules, whileremaining within the spirit and scope of the present invention. In suchan application, the baffles preferably would be disposed at and protrudefrom an inboard side wall or portion of the diffuser element inboard ofthe respective LED.

Illumination sources 28, 30 are energized to direct or emit illuminationalong the diffuser element so that the indicator/light is viewablethrough the reflective element, while the baffles 34 limit directviewing of the light emitting diodes so that bright spots are limited orreduced. The illumination sources 28, 30 may comprise any suitableillumination source or light source. For example, the illuminationsources may comprise one or more light emitting diodes (LEDs) or organiclight emitting diodes (OLEDs) or the like, or may comprise one or morepower LEDs, such as of the types described in U.S. Pat. No. 7,195,381,which is hereby incorporated herein by reference in its entirety, or maycomprise a LUXEON® LED available from LUMILEDSTM or other suitable lightsource.

The illumination sources 28, 30 may be controlled or operated via anysuitable circuitry and/or control. For example, a circuit may beoperable to power the LEDs without overvoltage protection (such as shownin FIG. 15 ) or a circuit may be operable to power the LEDs withovervoltage protection (such as shown in FIG. 16 ). When powered, theLEDs may provide up to about 11,000 nits minimum average brightness atnominal supply voltage (such as between about 9 and 16 volts DC, such asabout 13.5 Volts DC), with a generally uniform illumination. The LEDsmay emit colored light or white light, depending on the particularapplication, and may operate at a maximum current of about 100 mA andmay be operable at temperatures between about −30 degrees C. and +65degrees C.

Optionally, a light directing or light turning film or element may bedisposed at the rear of the glass substrate. Such a light directing filmmay direct or angle the light emitted by the illumination sources in thedesired direction (such as towards the driver of the vehicle).Optionally, such a light directing film may be part of the diffuserelement (close to the rear surface of the mirror reflective element).The light directing film may allow the module depth to be reduced and/ormay allow the circuit board and light sources or LEDs to be configuredto be closer to parallel (less angled) to the rear surface of the mirrorreflective element. The light directing film may comprise any suitablelight directing film that may direct or bend or angle light passingthrough the film, such as, for example, a direction turning film (DTF)of the types commercially available from Luminit, LLC of Torrance, CA,or the like.

Optionally, a heater pad 40 (FIG. 12 ) may be provided at the rearsurface of the glass substrate of the reflective element and between thebacking portion of the back plate and the reflective element to providean anti-fogging of de-fogging feature to the exterior mirror assembly(such as by utilizing aspects of the heater elements or pads describedin U.S. Pat. No. 7,400,435, which is hereby incorporated herein byreference in its entirety). The back plate and/or heater pad may includesuitable electrical connectors and connections incorporated therein(such as by utilizing aspects of the mirror assembly described in U.S.Pat. No. 7,400,435) for electrically connecting the heater pad and/orindicator module and/or display element (or other suitable electricalconnectors may be utilized, such as electrical leads or wire harnessesor pigtails or other separate connectors or cables or the like). Theheater pad may include a hole or opening or aperture therethrough (oroptionally a window or transparent or translucent or diffuse portion ofthe heater pad, such as a clear or diffusing transparent polyesterflexible plastic film or element) that generally corresponds to theaperture of the back plate when the heater pad is attached to the rearsurface of the glass substrate of the reflective element and when theback plate is attached to the rear surface of the heater pad.Optionally, and desirably, the heater pad may include an adhesive layer(such as a pressure sensitive adhesive layer) at its rear surface foradhering the back plate to the heater pad and thus to the rear surfaceof the glass substrate of the reflective element.

Optionally, and with reference to FIGS. 17-20 , a signal indicationmodule 122 includes louvers 134 disposed at and between the lightsources to provide the desired directionality of light emitted by themodule. Signal indication module 122 includes a housing 124 (that isreceived into or attached to an indicator receiving portion or mountingportion or structure of the mirror back plate so as to be disposedgenerally at a rear surface of a planar portion of the back plate) andan illumination source or indicator, such as one or more light emittingdiodes (LEDs) 128 or other suitable illumination source. In theillustrated embodiment, the light source comprises three light emittingdiodes 128, with each light emitting diode optionally beingindependently energized or powered for illuminating one or more icons(such as a respective icon associated with an individual LED)established at a mask 136 disposed at a front diffuser 138 of theindicator module (the mask may be a separate element with the icon orindicia is formed therethrough, or may comprise an icon or indiciaestablished at or through or partially through the mirror reflector ofthe reflective element). Signal indication module 122 includes adiffuser element 126 that is formed to angle the light emitted by thelight emitting diodes 128 such that light emitted by the light emittingdiodes, when activated or energized or powered, is principally viewed bythe driver of the vehicle. The indicator module 122 may be similar toindicator module 22, discussed above (and optionally an indicator moduleof the present invention may include both louvers and baffles), suchthat a detailed discussion of the indicator modules need not be repeatedherein.

The diffuser element 126 includes louvers 134 disposed between and infront of pairs of adjacent or respective light emitting diodes to director guide or angle the light emitted by the light emitting diodes at thefront diffuser to provide enhanced directionality of the emitted light.The louvers 134 are disposed or formed or established at the diffuserelement 126 (which may have polished surfaces at and around the ports orapertures that are aligned with the LEDs 128 to enhance theillumination) and angled at a desired amount to provide the desired orappropriate directionality of the light emitted by the LEDs. In theillustrated embodiment, the indicator module comprises a pair of louvers134 that are generally parallel to one another and that may be generallyparallel to the respective walls of the diffuser element. The surfacesof the louvers are angled relative to the plane of the front surface ofthe diffuser element to provide the desired or selected directing orguiding of light emitted by the LEDs. Thus, the emitted light may bedirected so as to be viewable by the driver of the subject vehicle andnot substantially viewable by driver(s) of other vehicles (for a blindzone indicator application, where the louvers may help to achieve OEMangle requirements for such blind zone indicators) or the emitted lightmay be viewable by a driver of another vehicle overtaking the subjectvehicle in an adjacent side lane (for a turn signal indicatorapplication) while not being substantially viewable by the driver of thesubject vehicle, depending on the particular application of theindicator module.

As shown in FIGS. 21-24 , the louvers are angled relative to thediffuser element front surface to provide the desired inboard oroutboard directing of light emitted by the LEDs that are disposed behindand aligned with the ports or apertures formed through the diffuserelement. The masking element (not shown in FIGS. 21-24 ) is disposed atthe front surface of the diffuser element to provide the desired iconsor indicia at the mirror reflective element when the illumination moduleis activated. For example, a lane change assist (LCA) icon (FIG. 25 )may be provided at the mask or masking element 136 or a blind zoneindicator (BZI) icon (FIG. 26 ) may be provided at the mask or maskingelement 136′, depending on the particular application of the indicatormodule. Thus, when the LEDs 128 are activated, the desired or selectedicons or indicia are viewable at the mirror reflective element by thedriver of the vehicle (or by drivers of other vehicles for a turn signalindicator application). The indicator module may have any desired shapedepending on the particular application. For example, a reduced sizeindicator module 122′ (FIG. 27 ) may be provided where the diffuserelement 126′ (with louvers 134′) and housing 124′ are generally formedto correspond to the circuit board shape and LED arrangement.

The louvers assist in achieving the OEM angle requirements for a BlindZone Indicator. Optionally, it is envisioned that such a louver conceptmay be used for other directional light requirements at the mirrorassembly, such as turn signal indicators or the like. Optionally, thediffuser may include louvers in between the light emitting diodes todirect illumination or block from the light sources or LEDs and thus tomeet angle specifications when the indicator is activated and viewed bya person viewing the mirror assembly.

In the illustrated embodiments of FIGS. 17-27 , the LEDs are generallylinearly arranged at the circuit board of the illumination module, butclearly the LEDs may be otherwise arranged depending on the particularapplication of the illumination module. For example, and with referenceto FIGS. 28 and 29 , an illumination module 222 includes a housing 224(that is received into or attached to an indicator receiving portion ormounting portion or structure of the mirror back plate so as to bedisposed generally at a rear surface of a planar portion of the backplate) and three light emitting diodes (LEDs) 228 arranged in agenerally triangular manner, with the light emitting diode optionallybeing cooperatively or independently energized or powered forilluminating one or more icons (such as a respective icon associatedwith an individual LED) established at a mask 236 disposed at a frontdiffuser 238 of the indicator module. Signal indication module 222includes a diffuser element 226 that has louvers 234 (FIG. 28 ) that areformed to angle or direct the light emitted by the light emitting diodes228 in the desired manner. The triangle shape with louvers between theLEDs may help to scatter the light giving better uniformity of lightemitted by the indicator module 222. The indicator module 222 may beotherwise similar to indicator modules 22, 122, 122′ discussed above,such that a detailed discussion of the indicator modules need not berepeated herein.

The inner surface of the diffuser element may be polished to enhancereflection of the emitted light to enhance viewability of the iconthrough the mirror reflective element. Optionally, the polishing orsurface finish of the diffuser element may be selected to provide thedesired degree of reflectivity and light emittance by the indicatormodule. In order to reduce hot spots or the like, baffles (such asdiscussed above) may be disposed in front of the LEDs (and between thelouvers). Optionally, the indicator module may be operable to provide adesired brightness or intensity of illumination and the desireddirectionality. The relative brightness of the LEDs may be balanced withcurrent shunts and the LEDs may be driven with less current which mayhelp to meet light reduction specifications without use of the bafflesdiscussed above.

The back plate and/or signal indication module may be formed to providea desired shape for viewing of the light passing through the reflectiveelement or the mirror reflective element preferably includes one or moreiconistic display areas or masks so that the illumination is viewableand discernible at the reflective element by the desired or targetedviewer. The mirror assembly thus may provide an iconistic display for anobject detection/LCA system and/or an iconistic display for a turnsignal indication, and/or may provide other displays or illuminationdevices, without affecting the scope of the present invention.

The indicator mounting portion may be angled so as to direct the lighttoward the vehicle and toward a driver or occupant of the host vehicle.More particularly, the light beam emitted from the blind spot signalindicating module and transmitted through the reflective element isangled so as to have its principle beam axis directed generally towardthe eyes of a driver seated in the interior cabin of the host vehicle.The indicator mounting portion thus may extend from the rear of the backplate at an acute angle (such as approximately about 25 to about 30degrees or thereabouts) relative to the plane defined by the back plateso as to direct or guide light through the passageway and in the desireddirection toward the side of the equipped/host vehicle for viewing theobject/LCA indication principally or solely by the driver of the hostvehicle. Should, however, the signal module be a turn signal module,then the indicator mounting portion may extend from the rear of the backplate at an acute angle (such as approximately about 55 to about 60degrees or thereabouts) relative to the plane defined by the back plateso as to direct or guide light through the passageway and in the desireddirection away from the side of the equipped/host vehicle for viewingthe turn indication principally or solely by the drivers of overtakingvehicles and principally other than by the driver of the host vehicle.

Optionally, it is envisioned that the signal indication module may beformed at an angle that is suitable for either application (blind spotalert and turn signal indication), such as about 30 degrees orthereabouts relative to the rear surface of the mirror substrate. Withsuch a construction, a common module may be used for either applicationby flipping the module or reversing the module so that in one position,the module is angled so as to direct illumination toward the driver ofthe subject vehicle and in the other position, the module is angled soas to direct illumination toward drivers of other vehicles approachingor overtaking the subject vehicle. The indicia element may be reversedas well (depending on the icon or indicia established thereon) or may beselected and added for the particular application (for example, awarning icon may be provided on modules adapted for use as a blind spotalert while a chevron symbol or the like may be provided on modulesadapted for use as a turn signal indicator). Thus, the different modulesmay have common molded housings and cover elements and circuitry, andthus may be readily manufactured and supplied for the particularapplications of the vehicles.

The back plate may comprise any suitable back plate structure, and maybe molded or formed, such as by injection molding, so as to provide thedisplay receiving portion and a generally planar backing portion thatattaches to the rear surface of the reflective element (such as viaadhesive or other suitable attachment means). As shown in FIGS. 2-4 ,back plate 20 includes an aperture at the mounting portion such thatwhen signal indication module 22 is attached to the mounting portion ofback plate 20, the front end of housing 24 and the indicia element 36 ofsignal indication module 22 are positioned through the aperture and ator against the rear surface of the reflective element substrate.Preferably, back plate 20 is molded of a substantially dark or opaque orblack material, such as from an ABS or polycarbonate polymeric resinmaterial or from any other suitable material such as known in theexterior rearview mirror art, so as to be substantially opaque such thatlight does not pass through the opaque back plate and the indicatormounting portion.

Optionally, and desirably, the indicator mounting portion may beunitarily or integrally formed with back plate 20 and may be formed witha pocket for receiving or partially receiving housing 24 to locatesignal indication module 22 at the generally planar backing portion ofback plate 20. For example, the pocket may receive housing 24 at leastpartially therein, and the indicator mounting portion may secure (suchas by snapping or the like) the housing at or in the pocket of theindicator mounting portion of back plate 20 (such as via tabs on theback plate engaging flanges or surfaces of the module housing to snapthe signal indication module 22 to the back plate with the forward endof the housing and the indicia element urged toward and against the rearsurface of the reflective element).

Optionally, the back plate may include a perimeter framing portion orbezel portion that extends around the perimeter edges of the reflectiveelement to support the reflective element and frame the reflectiveelement at the mirror assembly (such as by utilizing aspects of themirror assemblies described in U.S. Pat. Nos. 8,058,977 and/or7,581,859, which are hereby incorporated herein by reference in theirentireties). The perimeter bezel portion may be narrow or smalldepending on the particular application of the reflective element andmirror reflector sub-assembly. Optionally, the mirror reflectorsub-assembly may comprise a bezelless or frameless reflective element(such as the types described in U.S. Publication No. US-2006-0061008and/or U.S. Pat. Nos. 7,184,190 and/or 7,255,451, and/or InternationalPublication No. WO 2006/124682, which are hereby incorporated herein byreference in their entireties), whereby the back plate may not include aperimeter framing portion or bezel portion around the perimeter of thereflective element.

Back plate 20 may include an attachment element or elements (such as anannular ring or tab or annular prongs or annular snaps or the like)formed or established at the rear of the backing portion for attachingthe back plate 20 and reflective element 18 to a mirror actuator (suchas a mirror actuator as known in the art and/or as described in U.S.Pat. Nos. 7,080,914; 7,073,914; 6,916,100; 6,755,544; 6,685,864;6,467,920; 6,362,548; 6,243,218; 6,229,226; 6,213,612; 5,986,364 and/or5,900,999, which are hereby incorporated herein by reference herein intheir entireties), which is adjustable or operable to adjust a viewingangle of the mirror reflective element. When the mirror reflectiveelement is canted or angled partially toward the driver of the hostvehicle (which is typically the orientation of the reflective elementduring use so as to provide a generally rearward field of view to thedriver of the host vehicle), there is sufficient space within the mirrorcasing at or near the outboard portion of the mirror assembly for theindicator mounting portion and signal indication module. The back plateand signal indication module of the present invention thus utilizes thespace within the mirror head or casing that is already available andtypically not used or occupied by other components.

Optionally, and preferably, indicator element or display element orsignal indication module may snap into the end or pocket of theindicator mounting portion or may otherwise be attached or stuck at theindicator mounting portion, and may have a gasket or seal at the signalindication module to provide a substantially water proof or waterresistant or water tight seal at the signal indication module, wherebythe signal indication module may be sealed at the indicator mountingportion, such as by gluing or pressing or screwing or gasketing orhermetically sealing or otherwise substantially sealing the signalindication module at the indicator mounting portion. The signalindication module may comprise a self-contained, unitary, sealed orsubstantially sealed, indicator module that includes the housing andcover element, an illumination source (such as one or more LEDs or thelike), a DC converter with a voltage dropping resistor (such asdescribed in U.S. Pat. Nos. 7,195,381; 6,902,284 and/or 6,690,268, whichare hereby incorporated herein by reference in their entireties) and theelectrical terminals or connector. The signal indication module thus maybe connected to a power source and may be activated or energized toilluminate the display for viewing by the driver of the vehicle.Optionally, the electrical connections to the signal indication modulemay be made while the signal indication module is attached to the mirrorassembly, such as via a plug and socket type arrangement orconfiguration, and such as by utilizing aspects of the mirror assemblydescribed in U.S. Pat. No. 6,669,267, which is hereby incorporatedherein by reference in its entirety. The unitary signal indicationmodule may include or utilize aspects of various light modules orsystems or devices, such as the types described in U.S. Pat. Nos.7,581,859; 6,227,689; 6,582,109; 5,371,659; 5,497,306; 5,669,699;5,823,654; 6,176,602 and/or 6,276,821, and/or International PublicationNo. WO 2006/124682, which are hereby incorporated herein by reference intheir entireties.

The blind spot indicators of the present invention thus are operable toprovide an indication to the driver of the host vehicle that an objector other vehicle has been detected in the lane or area adjacent to theside of the host vehicle. The blind spot indicator may be operable inassociation with a blind spot detection system, which may include animaging sensor or sensors, or an ultrasonic sensor or sensors, or asonar sensor or sensors or the like. For example, the blind spotdetection system may utilize aspects of the blind spot detection and/orimaging systems described in U.S. Pat. Nos. 7,881,496; 7,720,580;7,038,577; 6,882,287; 6,198,409; 5,929,786 and/or 5,786,772, and/or ofthe reverse or backup aid systems, such as the rearwardly directedvehicle vision systems described in U.S. Pat. Nos. 5,550,677; 5,760,962;5,670,935; 5,877,897; 6,201,642; 6,396,397; 6,498,620; 6,717,610;6,757,109 and/or 7,005,974, and/or of the automatic headlamp controlsdescribed in U.S. Pat. Nos. 7,526,103; 5,796,094 and/or 5,715,093,and/or of the rain sensors described in U.S. Pat. Nos. 6,250,148 and/or6,341,523, and/or of other imaging systems, such as the types describedin U.S. Pat. Nos. 6,353,392 and/or 6,313,454, which may utilize variousimaging sensors or imaging array sensors or cameras or the like, such asa CMOS imaging array sensor, a CCD sensor or other sensors or the like,such as the types disclosed in commonly assigned, U.S. Pat. Nos.5,550,677; 5,760,962 and/or 5,796,094, and/or International PublicationNo. WO 2004/047421, with all of the above referenced U.S. patents andPCT applications being commonly assigned and being hereby incorporatedherein by reference in their entireties.

The reflective element of the rearview mirror assembly may comprise anelectro-optic or electrochromic reflective element or cell, such as anelectrochromic mirror assembly and electrochromic reflective elementutilizing principles disclosed in commonly assigned U.S. Pat. Nos.7,626,749; 6,690,268; 5,140,455; 5,151,816; 6,178,034; 6,154,306;6,002,544; 5,567,360; 5,525,264; 5,610,756; 5,406,414; 5,253,109;5,076,673; 5,073,012; 5,117,346; 5,724,187; 5,668,663; 5,910,854;5,142,407; 4,712,879; 7,195,381 and/or 7,255,451, and/or InternationalPublication No. WO 2006/124682, which are all hereby incorporated hereinby reference in their entireties.

Optionally, the reflective element may include a perimeter metallicband, such as the types described in U.S. Pat. Nos. 7,255,451 and7,274,501, and International Publication Nos. WO 2004/026633 and/or WO2004/042457, which are all hereby incorporated herein by reference intheir entireties. Optionally, the reflective element may include indiciaformed at and viewable at the reflective element, such as by utilizingaspects of the reflective elements described in U.S. Pat. No. 7,626,749,which is hereby incorporated herein by reference in its entirety.

Optionally, the reflective element may comprise a single substrate witha reflective coating at its rear surface, without affecting the scope ofthe present invention. The mirror assembly thus may comprise a prismaticmirror assembly or planar or non-planar mirror or other mirror having asingle substrate reflective element, such as a mirror assembly utilizingaspects described in U.S. Pat. Nos. 7,249,860; 6,318,870; 6,598,980;5,327,288; 4,948,242; 4,826,289; 4,436,371 and/or 4,435,042, and/orInternational Publication No. WO 2004/103772, which are herebyincorporated herein by reference in their entireties. Optionally, thereflective element may comprise a conventional prismatic or flatreflective element or prism, or may comprise a prismatic or flatreflective element of the types described in International PublicationNos. WO 2004/026633 and/or WO 2004/103772, and/or U.S. Pat. Nos.7,420,756; 7,249,860; 7,255,451 and/or 7,338,177, which are all herebyincorporated herein by reference in their entireties, without affectingthe scope of the present invention.

Changes and modifications to the specifically described embodiments maybe carried out without departing from the principles of the presentinvention, which is intended to be limited only by the scope of theappended claims as interpreted according to the principles of patentlaw.

1. A vehicular exterior rearview mirror assembly, said vehicularexterior rearview mirror assembly comprising: a mounting structureconfigured for attaching at a side region of a vehicle to mount saidvehicular exterior rearview mirror assembly at the vehicle; a mirrorreflective element; a mirror back plate; wherein said mirror back platecomprises an aperture formed therethrough; said mirror back platecomprising a front side and a rear side separated from the front side bya thickness dimension of said mirror back plate; wherein the front sideof said mirror back plate is attached at a rear side of said mirrorreflective element; a heater element disposed between the front side ofsaid mirror back plate and the rear side of said mirror reflectiveelement; wherein the rear side of said mirror back plate is attached atan electrically operated mirror actuator; wherein, with said vehicularexterior rearview mirror assembly mounted at the vehicle, and when saidmirror actuator is electrically operated, said mirror back plate andsaid mirror reflective element move in tandem relative to said mountingstructure to adjust a rearward view of a driver of the vehicle who isviewing said mirror reflective element; a blind zone indication modulecomprising a circuit element with circuitry disposed thereat, whereinsaid circuitry comprises a light source; wherein said light sourcecomprises a plurality of light emitting diodes; said blind zoneindication module comprising a diffuser; wherein said blind zoneindication module is located at the aperture formed through said mirrorback plate; wherein said blind zone indication module adhesivelyattaches at the rear side of said mirror reflective element via theaperture formed through said mirror back plate; wherein said blind zoneindication module includes a housing that houses said circuit elementand said light source therein; wherein said circuit element comprises aplurality of electrically conductive terminals in electrical connectionwith circuitry of said circuit element; wherein said plurality ofelectrically conductive terminals is disposed at a connector portion ofsaid housing and is accessible thereat; wherein said circuitry isoperable to electrically power said light source; wherein said connectorportion of said housing is configured to connect said plurality ofelectrically conductive terminals to a wire harness to electricallypower circuitry of said circuit element when said vehicular exteriorrearview mirror assembly is mounted and used at the vehicle; whereinsaid light source, when electrically powered by said circuitry, emitslight having a brightness of at least 11,000 nits when at least 9 voltsDC is provided to said circuitry; and wherein said blind zone indicationmodule is associated with a blind spot detection system of the vehicleat which said vehicular exterior rearview mirror assembly is mounted andused.
 2. The vehicular exterior rearview mirror assembly of claim 1,wherein the rear side of said mirror back plate comprises an indicatorreceiving portion located at the aperture formed through said mirrorback plate, and wherein said indicator receiving portion at leastpartially receives said housing.
 3. The vehicular exterior rearviewmirror assembly of claim 1, wherein said connector portion extends froma side wall of said housing, and wherein said connector portion of saidhousing and said plurality of electrically conductive terminals extendover the rear side of said mirror reflective element.
 4. The vehicularexterior rearview mirror assembly of claim 1, wherein said housingcomprises an inner surface, and wherein the inner surface comprises adiffusely light reflecting surface for reflecting light incident thereonto enhance intensity of light that exits said blind zone indicationmodule.
 5. The vehicular exterior rearview mirror assembly of claim 1,wherein each light emitting diode of said plurality of light emittingdiodes is associated with a respective icon of an indicia elementdisposed at an end portion of said blind zone indication module that isat said mirror reflective element.
 6. The vehicular exterior rearviewmirror assembly of claim 1, wherein said plurality of light emittingdiodes comprises three triangularly arranged light emitting diodes. 7.The vehicular exterior rearview mirror assembly of claim 6, wherein saidblind zone indication module comprises first, second and third louversestablished between respective pairs of light emitting diodes of saidthree triangularly arranged light emitting diodes.
 8. The vehicularexterior rearview mirror assembly of claim 1, wherein said mirror backplate comprises a plastic mirror back plate.
 9. The vehicular exteriorrearview mirror assembly of claim 1, wherein said heater elementcomprises a light transmitting portion that corresponds to the apertureformed through said mirror back plate when the front side of said mirrorback plate is attached at the rear side of said mirror reflectiveelement.
 10. A vehicular exterior rearview mirror assembly, saidvehicular exterior rearview mirror assembly comprising: a mountingstructure configured for attaching at a side region of a vehicle tomount said vehicular exterior rearview mirror assembly at the vehicle; amirror reflective element; a mirror back plate; wherein said mirror backplate comprises an aperture formed therethrough; said mirror back platecomprising a front side and a rear side separated from the front side bya thickness dimension of said mirror back plate; wherein the front sideof said mirror back plate is attached at a rear side of said mirrorreflective element; a heater element disposed between the front side ofsaid mirror back plate and the rear side of said mirror reflectiveelement; wherein the rear side of said mirror back plate is attached atan electrically operated mirror actuator; wherein, with said vehicularexterior rearview mirror assembly mounted at the vehicle, and when saidmirror actuator is electrically operated, said mirror back plate andsaid mirror reflective element move in tandem relative to said mountingstructure to adjust a rearward view of a driver of the vehicle who isviewing said mirror reflective element; a blind zone indication modulecomprising a circuit element with circuitry disposed thereat, whereinsaid circuitry comprises a light source; wherein said light sourcecomprises a plurality of light emitting diodes; said blind zoneindication module comprising a diffuser; wherein said blind zoneindication module snap attaches at the rear side of said mirror backplate; wherein said blind zone indication module includes a housing thathouses said circuit element and said light source therein; wherein saidcircuit element comprises a plurality of electrically conductiveterminals in electrical connection with circuitry of said circuitelement; wherein said plurality of electrically conductive terminals isdisposed at a connector portion of said housing and is accessiblethereat; wherein said circuitry is operable to electrically power saidlight source; wherein said connector portion of said housing isconfigured to connect said plurality of electrically conductiveterminals to a wire harness to electrically power circuitry of saidcircuit element when said vehicular exterior rearview mirror assembly ismounted and used at the vehicle; wherein said light source, whenelectrically powered by said circuitry, emits light having a brightnessof at least 11,000 nits when at least 9 volts DC is provided to saidcircuitry; and wherein said blind zone indication module is associatedwith a blind spot detection system of the vehicle at which saidvehicular exterior rearview mirror assembly is mounted and used.
 11. Thevehicular exterior rearview mirror assembly of claim 10, wherein saidmirror back plate comprises a plastic mirror back plate.
 12. Thevehicular exterior rearview mirror assembly of claim 10, wherein saidheater element comprises a light transmitting portion that correspondsto the aperture formed through said mirror back plate when the frontside of said mirror back plate is attached at the rear side of saidmirror reflective element.
 13. The vehicular exterior rearview mirrorassembly of claim 10, wherein the rear side of said mirror back platecomprises an indicator receiving portion located at the aperture formedthrough said mirror back plate, and wherein said blind zone indicationmodule snap attaches at said indicator receiving portion.
 14. Thevehicular exterior rearview mirror assembly of claim 13, wherein saidindicator receiving portion at least partially receives said blind zoneindication module.
 15. The vehicular exterior rearview mirror assemblyof claim 13, wherein said indicator receiving portion at the rear sideof said mirror back plate at least partially circumscribes the apertureformed through said mirror back plate.
 16. The vehicular exteriorrearview mirror assembly of claim 10, wherein said connector portionextends from a side wall of said housing, and wherein said connectorportion of said housing and said plurality of electrically conductiveterminals extend over the rear side of said mirror reflective element.17. The vehicular exterior rearview mirror assembly of claim 10, whereinsaid housing comprises an inner surface, and wherein the inner surfacecomprises a diffusely light reflecting surface for reflecting lightincident thereon to enhance intensity of light that exits said blindzone indication module.
 18. The vehicular exterior rearview mirrorassembly of claim 10, wherein each light emitting diode of saidplurality of light emitting diodes is associated with a respective iconof an indicia element disposed at an end portion of said blind zoneindication module that is at said mirror reflective element.
 19. Thevehicular exterior rearview mirror assembly of claim 10, wherein saidplurality of light emitting diodes comprises three triangularly arrangedlight emitting diodes.
 20. The vehicular exterior rearview mirrorassembly of claim 19, wherein said blind zone indication modulecomprises first, second and third louvers established between respectivepairs of light emitting diodes of said three triangularly arranged lightemitting diodes.
 21. A vehicular exterior rearview mirror assembly, saidvehicular exterior rearview mirror assembly comprising: a mountingstructure configured for attaching at a side region of a vehicle tomount said vehicular exterior rearview mirror assembly at the vehicle; amirror reflective element; a mirror back plate; wherein said mirror backplate comprises an aperture formed therethrough; said mirror back platecomprising a front side and a rear side separated from the front side bya thickness dimension of said mirror back plate; wherein the front sideof said mirror back plate is attached at a rear side of said mirrorreflective element; a heater element disposed between the front side ofsaid mirror back plate and the rear side of said mirror reflectiveelement; wherein the rear side of said mirror back plate is attached atan electrically operated mirror actuator; wherein, with said vehicularexterior rearview mirror assembly mounted at the vehicle, and when saidmirror actuator is electrically operated, said mirror back plate andsaid mirror reflective element move in tandem relative to said mountingstructure to adjust a rearward view of a driver of the vehicle who isviewing said mirror reflective element; a blind zone indication modulecomprising a circuit element with circuitry disposed thereat, whereinsaid circuitry comprises a light source; wherein said light sourcecomprises a plurality of light emitting diodes; said blind zoneindication module comprising a diffuser; wherein said blind zoneindication module includes a housing that houses said circuit elementand said light source therein; wherein the rear side of said mirror backplate comprises an indicator receiving portion located at an apertureformed through said mirror back plate; wherein said blind zoneindication module snap attaches at the indicator receiving portion atthe rear side of said mirror back plate; wherein said indicatorreceiving portion at least partially receives said housing when saidblind zone indication module snap attaches at the indicator receivingportion at the rear side of said mirror back plate; wherein said circuitelement comprises a plurality of electrically conductive terminals inelectrical connection with circuitry of said circuit element; whereinsaid plurality of electrically conductive terminals is disposed at aconnector portion of said housing and is accessible thereat; whereinsaid circuitry is operable to electrically power said light source;wherein said connector portion of said housing is configured to connectsaid plurality of electrically conductive terminals to a wire harness toelectrically power circuitry of said circuit element when said vehicularexterior rearview mirror assembly is mounted and used at the vehicle;wherein said light source, when electrically powered by said circuitry,emits light having a brightness of at least 11,000 nits when at least 9volts DC is provided to said circuitry; and wherein said blind zoneindication module is associated with a blind spot detection system ofthe vehicle at which said vehicular exterior rearview mirror assembly ismounted and used.
 22. The vehicular exterior rearview mirror assembly ofclaim 21, wherein said connector portion extends from a side wall ofsaid housing, and wherein said connector portion of said housing andsaid plurality of electrically conductive terminals extend over the rearside of said mirror reflective element.
 23. The vehicular exteriorrearview mirror assembly of claim 21, wherein said housing comprises aninner surface, and wherein the inner surface comprises a diffusely lightreflecting surface for reflecting light incident thereon to enhanceintensity of light that exits said blind zone indication module.
 24. Thevehicular exterior rearview mirror assembly of claim 21, wherein eachlight emitting diode of said plurality of light emitting diodes isassociated with a respective icon of an indicia element disposed at anend portion of said blind zone indication module that is at said mirrorreflective element.
 25. The vehicular exterior rearview mirror assemblyof claim 21, wherein said plurality of light emitting diodes comprisesthree triangularly arranged light emitting diodes.
 26. The vehicularexterior rearview mirror assembly of claim 25, wherein said blind zoneindication module comprises first, second and third louvers establishedbetween respective pairs of light emitting diodes of said threetriangularly arranged light emitting diodes.
 27. The vehicular exteriorrearview mirror assembly of claim 21, wherein said mirror back platecomprises a plastic mirror back plate.
 28. The vehicular exteriorrearview mirror assembly of claim 21, wherein said heater elementcomprises a light transmitting portion that corresponds to the apertureformed through said mirror back plate when the front side of said mirrorback plate is attached at the rear side of said mirror reflectiveelement.